bug#23551: 24.5; beginning-of-line wrong in repeated kbd macro

[abbott]

I would like to report the following bug.
Open the attached file in Emacs, and move point to the first position.
Define a keyboard macro: (I want to put each line inside double-quotes)
"                  ;; self-insert-command
C-e                     ;; move-end-of-line
"                  ;; self-insert-command
C-a                     ;; message-beginning-of-line
<down>                    ;; next-line

Now ask Emacs to repeat this macro 49 times.
The result is wrong: at around line 35, the first double-quote
is no longer at the start of the line; then on successive lines
the position of the first inserted double-quote walks to the right.

-----------------------------------------------------------------
In GNU Emacs 24.5.1 (i686-apple-darwin, NS apple-appkit-1038.36)
 of 2015-04-10 on builder10-6.porkrind.org
Windowing system distributor `Apple', version 10.3.1038
Configured using:
 `configure --with-ns '--enable-locallisppath=/Library/Application
 Support/Emacs/${version}/site-lisp:/Library/Application
 Support/Emacs/site-lisp' --host=i686-apple-darwin
 --build=i686-apple-darwin --with-jpeg=no --with-png=no --with-gif=no
 --with-tiff=no'

Important settings:
  locale-coding-system: utf-8-unix

Major mode: Fundamental

Minor modes in effect:
  recentf-mode: t
  show-paren-mode: t
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
Cleaning up the recentf list...
File /Users/abbott/ShortTerm/EMACS-BUG-orig removed from the recentf list
Cleaning up the recentf list...done (1 removed)
Loading /Users/abbott/Work/CoCoA/CoCoA4/4.7/UI/emacs/cocoa.emacs...done
Loading  
/Users/abbott/Work/CoCoA/CoCoA5/CoCoALib-0.99/src/CoCoA-5/emacs/cocoa5.emacs...done
Loading rmail-spam-filter.elc...done
For information about GNU Emacs and the GNU system, type C-h C-a.
Defining kbd macro...
Keyboard macro defined
(Type e to repeat macro)

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr warnings emacsbug sendmail cl-extra
info magit-autoloads git-rebase-mode-autoloads git-commit-mode-autoloads
package epg-config rmail-spam-filter rmailsum rmail recentf tree-widget
wid-edit git-blame git derived log-edit easy-mmode message cl-macs
format-spec rfc822 mml easymenu mml-sec mm-decode mm-bodies mm-encode
mail-parse rfc2231 rfc2047 rfc2045 ietf-drums mm-util help-fns
mail-prsvr mailabbrev mail-utils gmm-utils mailheader ring pcvs-util
add-log ewoc cl gv paren cus-start cus-load edmacro kmacro cl-loaddefs
cl-lib time-date tooltip electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel ns-win tool-bar dnd fontset image regexp-opt
fringe tabulated-list newcomment lisp-mode prog-mode register page
menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock
syntax facemenu font-core frame cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese hebrew greek
romanian slovak czech european ethiopic indian cyrillic chinese
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer nadvice
loaddefs button faces cus-face macroexp files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process cocoa ns
multi-tty emacs)

Memory information:
((conses 8 143707 11759)
 (symbols 24 23822 0)
 (miscs 20 100 224)
 (strings 16 30397 6332)
 (string-bytes 1 745514)
 (vectors 8 14455)
 (vector-slots 4 436468 9860)
 (floats 8 71 198)
 (intervals 28 254 26)
 (buffers 512 14))

EMACS-BUG
Description: Text document